Compositions containing difluoromethane, tetrafluoropropene, and carbon dioxide and uses thereof

ABSTRACT

In accordance with the present invention refrigerant compositions are disclosed. The compositions comprise a refrigerant mixture consisting essentially of HFC-32, HFO-1234yf, and CO2. The compositions are useful in processes to produce cooling and heating, in methods for replacing refrigerant R-32, and in refrigeration, air conditioning or heat pump systems. These inventive compositions are match cooling performance for R-32 with GWP less than 400 or less than 300.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates to compositions for use in airconditioning or heat pump systems. In particular, the compositions ofthe present invention are useful in methods for producing cooling andheating, and methods for replacing R-32 and air conditioning and heatpump apparatus.

2. Description of Related Art

The refrigeration industry has been working for the past few decades tofind replacement refrigerants for the ozone-depletingchlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) beingphased out as a result of the Montreal Protocol. The solution for mostrefrigerant producers has been the commercialization ofhydrofluorocarbon (HFC) refrigerants. These HFC refrigerants,including-134a, R-32 and R-410A, among others, have zero ozone depletionpotential and thus are not affected by the current regulatory phase outas a result of the original Montreal Protocol. With implementation tothe Kigali amendment to the Montreal Protocol, even lower GWPreplacement refrigerants are being sought.

BRIEF SUMMARY

Certain compositions comprising difluoromethane, tetrafluoropropene andcarbon dioxide have been found to possess suitable properties to allowtheir use as replacements for currently available commercialrefrigerants, in particular R-32, with relatively high GWP. Therefore,the present inventors have discovered refrigerant gases that arenon-ozone depleting, and have significantly less direct global warmingpotential than and match the performance of R-32, and are thus,environmentally sustainable alternatives.

In accordance with the present invention refrigerant compositions aredisclosed. The compositions comprise refrigerant mixtures consistingessentially of difluoromethane, tetrafluoropropene and carbon dioxide.

The refrigerant are useful as components in compositions also containingnon-refrigerant components (e.g., lubricants and/or additives), inprocesses to produce cooling or heating, in methods for replacingrefrigerant R-32, and, in particular, in air conditioning and heat pumpapparatus.

DETAILED DESCRIPTION

Before addressing details of embodiments described below, some terms aredefined or clarified.

Definitions

As used herein, the term heat transfer fluid (also referred to as heattransfer medium) means a composition used to carry heat from a heatsource to a heat sink.

A heat source is defined as any space, location, object or body fromwhich it is desirable to add, transfer, move or remove heat. Examples ofheat sources are spaces (open or enclosed) requiring refrigeration orcooling, such as refrigerator or freezer cases in a supermarket,transport refrigerated containers, building spaces requiring airconditioning, industrial water chillers or the passenger compartment ofan automobile requiring air conditioning. In some embodiments, the heattransfer composition may remain in a constant state throughout thetransfer process (i.e., not evaporate or condense). In otherembodiments, evaporative cooling processes may utilize heat transfercompositions as well.

A heat sink is defined as any space, location, object or body capable ofabsorbing heat. A vapor compression refrigeration system is one exampleof such a heat sink.

A refrigerant is defined as a heat transfer fluid that undergoes a phasechange from liquid to gas and back again during a cycle used to transferof heat.

A heat transfer system is the system (or apparatus) used to produce aheating or cooling effect in a particular space. A heat transfer systemmay be a mobile system or a stationary system.

Examples of heat transfer systems are any type of refrigeration systemsand air conditioning systems including, but are not limited to,stationary heat transfer systems, air conditioners, freezers,refrigerators, heat pumps, water chillers, flooded evaporator chillers,direct expansion chillers, walk-in coolers, mobile refrigerators, mobileheat transfer systems, mobile air conditioning units, dehumidifiers, andcombinations thereof.

Refrigeration capacity (also referred to as cooling capacity) is a termwhich defines the change in enthalpy of a refrigerant in an evaporatorper pound of refrigerant circulated, or the heat removed by therefrigerant in the evaporator per unit volume of refrigerant vaporexiting the evaporator (volumetric capacity).

The refrigeration capacity is a measure of the ability of a refrigerantor heat transfer composition to produce cooling. Therefore, the higherthe capacity, the greater the cooling that is produced. Cooling raterefers to the heat removed by the refrigerant in the evaporator per unittime.

Coefficient of performance (COP) is the amount of heat removed dividedby the required energy input to operate the cycle. The higher the COP,the higher is the energy efficiency. COP is directly related to theenergy efficiency ratio (EER) that is the efficiency rating forrefrigeration or air conditioning equipment at a specific set ofinternal and external temperatures.

The term “subcooling” refers to the reduction of the temperature of aliquid below that liquid's saturation point for a given pressure. Thesaturation point is the temperature at which the vapor is completelycondensed to a liquid, but subcooling continues to cool the liquid to alower temperature liquid at the given pressure. By cooling a liquidbelow the saturation temperature (or bubble point temperature), the netrefrigeration capacity can be increased. Subcooling thereby improvesrefrigeration capacity and energy efficiency of a system. Subcool amountis the amount of cooling below the saturation temperature (in degrees).

Superheat is a term that defines how far above its saturation vaportemperature (the temperature at which, if the composition is cooled, thefirst drop of liquid is formed, also referred to as the “dew point”) avapor composition is heated.

Temperature glide (sometimes referred to simply as “glide”) is theabsolute value of the difference between the starting and endingtemperatures of a phase-change process by a refrigerant within acomponent of a refrigerant system, exclusive of any subcooling orsuperheating. This term may be used to describe condensation orevaporation of a near azeotrope or non-azeotropic composition. Whenreferring to the temperature glide of a refrigeration, air conditioningor heat pump system, it is common to provide the average temperatureglide being the average of the temperature glide in the evaporator andthe temperature glide in the condenser.

The net refrigeration effect is the quantity of heat that each kilogramof refrigerant absorbs in the evaporator to produce useful cooling.

The mass flow rate is the quantity of refrigerant in kilogramscirculating through the refrigeration, heat pump or air conditioningsystem over a given period of time.

As used herein, the term “lubricant” means any material added to acomposition or a compressor (and in contact with any heat transfercomposition in use within any heat transfer system) that provideslubrication to the compressor to aid in preventing parts from seizing.

As used herein, compatibilizers are compounds which improve solubilityof the hydrofluorocarbon of the disclosed compositions in heat transfersystem lubricants. In some embodiments, the compatibilizers improve oilreturn to the compressor. In some embodiments, the composition is usedwith a system lubricant to reduce oil-rich phase viscosity.

As used herein, oil-return refers to the ability of a heat transfercomposition to carry lubricant through a heat transfer system and returnit to the compressor. That is, in use, it is not uncommon for someportion of the compressor lubricant to be carried away by the heattransfer composition from the compressor into the other portions of thesystem. In such systems, if the lubricant is not efficiently returned tothe compressor, the compressor will eventually fail due to lack oflubrication.

As used herein, “ultra-violet” dye is defined as a UV fluorescent orphosphorescent composition that absorbs light in the ultra-violet or“near” ultra-violet region of the electromagnetic spectrum. Thefluorescence produced by the UV fluorescent dye under illumination by aUV light that emits at least some radiation with a wavelength in therange of from 10 nanometers to about 775 nanometers may be detected.

Flammability is a term used to mean the ability of a composition toignite and/or propagate a flame. For refrigerants and other heattransfer compositions, the lower flammability limit (“LFL”) is theminimum concentration of the heat transfer composition in air that iscapable of propagating a flame through a homogeneous mixture of thecomposition and air under test conditions specified in ASTM (AmericanSociety of Testing and Materials) E681. The upper flammability limit(“UFL”) is the maximum concentration of the heat transfer composition inair that is capable of propagating a flame through a homogeneous mixtureof the composition and air under the same test conditions. Determinationof whether a refrigerant compound or mixture is flammable ornon-flammable is also done by testing under the conditions of ASTM-681.

During a refrigerant leak, lower boiling components of a mixture mayleak preferentially. Thus, the composition in the system, as well as,the vapor leaking can vary over the time period of the leak. Thus, anon-flammable mixture may become flammable under leakage scenarios. Andin order to be classified as non-flammable by ASHRAE (American Societyof Heating, Refrigeration and Air-conditioning Engineers), a refrigerantor heat transfer composition must be non-flammable as formulated, butalso under leakage conditions.

Global warming potential (GWP) is an index for estimating relativeglobal warming contribution due to atmospheric emission of a kilogram ofa particular greenhouse gas compared to emission of a kilogram of carbondioxide. GWP can be calculated for different time horizons showing theeffect of atmospheric lifetime for a given gas. The GWP for the 100 yeartime horizon is commonly the value referenced. For mixtures, a weightedaverage can be calculated based on the individual GWPs for eachcomponent.

Ozone depletion potential (ODP) is a number that refers to the amount ofozone depletion caused by a substance. The ODP is the ratio of theimpact on ozone of a chemical compared to the impact of a similar massof CFC-11 (fluorotrichloromethane). Thus, the ODP of CFC-11 is definedto be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0.HFCs and HFOs have zero ODP because they do not contain chlorine orother ozone depleting halogens.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a composition,process, method, article, or apparatus that comprises a list of elementsis not necessarily limited to only those elements but may include otherelements not expressly listed or inherent to such composition, process,method, article, or apparatus.

The transitional phrase “consisting of” excludes any element, step, oringredient not specified. If in the claim such would close the claim tothe inclusion of materials other than those recited except forimpurities ordinarily associated therewith. When the phrase “consistsof” appears in a clause of the body of a claim, rather than immediatelyfollowing the preamble, it limits only the element set forth in thatclause; other elements are not excluded from the claim as a whole.

The transitional phrase “consisting essentially of” is used to define acomposition, method or apparatus that includes materials, steps,features, components, or elements, in addition to those literallydisclosed provided that these additional included materials, steps,features, components, or elements do not materially affect the basic andnovel characteristic(s) of the claimed invention. The term ‘consistingessentially of’ occupies a middle ground between “comprising” and‘consisting of’. Typically, components of the refrigerant mixtures andthe refrigerant mixtures themselves can contain minor amounts (e.g.,less than about 0.5 weight percent total) of impurities and/orbyproducts (e.g., from the manufacture of the refrigerant components orreclamation of the refrigerant components from other systems) which donot materially affect the novel and basic characteristics of therefrigerant mixture.

Where applicants have defined an invention or a portion thereof with anopen-ended term such as “comprising,” it should be readily understoodthat (unless otherwise stated) the description should be interpreted toalso describe such an invention using the terms “consisting essentiallyof” or “consisting of.”

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the disclosed compositions,suitable methods and materials are described below. All publications,patent applications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

2,3,3,3-tetrafluoropropene may also be referred to as HFO-1234yf,HFC-1234yf, or R-1234yf. HFO-1234yf may be made by methods known in theart, such as by dehydrofluorination 1,1,1,2,3-pentafluoropropane(HFC-245eb) or 1,1,1,2,2-pentafluoropropane (HFC-245cb).

Difluoromethane (HFC-32 or R-32) is commercially available or may bemade by methods known in the art, such as by dechlorofluorination ofmethylene chloride.

Carbon dioxide (CO₂) is commercially available from many gas supplyhouses or may be produced by any of numerous well known methods.

Compositions

The refrigerants industry has struggled to develop new refrigerantproducts that provide acceptable performance and environmentalsustainability. New global warming regulations may place a cap on globalwarming potential (GWP) for new refrigerant compositions. Thus, theindustry must find, low GWP, low-toxicity, low ozone depletion potential(ODP) compositions that also provide good performance for cooling andheating. Difluoromethane (HFC-32, or R-32) has been found to havedesirable properties for a refrigerant or heat transfer composition, buthas a moderately high GWP, 675, and therefore, lower GWP replacementsfor HFC-32 are also being sought.

In one embodiment, refrigerant mixtures have GWP of 400 or less, basedon AR4 data. In another embodiment, refrigerant mixtures have GWP of 300or less, based on AR4 data.

The present inventors have identified refrigerant mixtures that provideperformance properties to serve as replacements for R-32 in airconditioning and heat pump apparatus. These compositions compriserefrigerant mixtures consisting essentially of difluoromethane,2,3,3,3-tetrafluoropropene, and carbon dioxide. In one embodiment, thecompositions comprising refrigerant mixtures consist of difluoromethane,2,3,3,3-tetrafluoropropene, and carbon dioxide.

Identifying replacement refrigerants with the right balance ofproperties needed by certain applications is not a trivial undertaking.The industry has struggled to find high capacity refrigerants withreasonable temperature glide. In particular, a refrigerant for replacingR-32 that can match the cooling capacity of R-32 with acceptabletemperature glide and with GWP of 400 or less, or even 300 or less hasbeen desired.

Disclosed herein are compositions comprising refrigerant mixtures forreplacing R-32 said refrigerant mixtures consisting essentially of fromabout 42 to about 59 weight percent difluoromethane (HFC-32), about 28to about 53 weight percent 2,3,3,3-tetrafluoropropene (HFO-1234yf), andabout 4 to about 17 weight percent carbon dioxide (CO₂).

In another embodiment, said refrigerant mixture consists essentially offrom about 42 to about 59 weight percent difluoromethane, about 31 toabout 49 weight percent 2,3,3,3-tetrafluoropropene, and about 4 to about17 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consists essentially offrom about 42 to about 59 weight percent difluoromethane, about 33 toabout 48 weight percent 2,3,3,3-tetrafluoropropene, and about 6 to about15 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consists essentially ofabout 42 to 59 weight percent difluoromethane, about 33 to 46 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 17 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consists essentially ofabout 47 to 59 weight percent difluoromethane, about 32 to 47 weightpercent 2,3,3,3-tetrafluoropropene, and about 8 to 13 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 47 to 59 weight percent difluoromethane, about 28 to 46 weightpercent 2,3,3,3-tetrafluoropropene, and about 4 to 16 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 47 to 59 weight percent difluoromethane, about 31 to 44 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 13 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 47 to 59 weight percent difluoromethane, about 32 to 42 weightpercent 2,3,3,3-tetrafluoropropene, and about 8 to 12 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 42 to 59 weight percent difluoromethane, about 32 to 45 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 15 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 44 to 59 weight percent difluoromethane, about 32 to 45 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 15 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 44 to 47 weight percent difluoromethane, about 45 to 50 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 15 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 42 to 44 weight percent difluoromethane, about 45 to 50 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 13 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 42 to 44 weight percent difluoromethane, about 48 to 49 weightpercent 2,3,3,3-tetrafluoropropene, and about 7 to 10 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 43 to 44 weight percent difluoromethane, about 48 to 49 weightpercent 2,3,3,3-tetrafluoropropene, and about 6 to 8 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 44 weight percent difluoromethane, about 49 weight percent2,3,3,3-tetrafluoropropene, and about 7 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 43 to 45 weight percent difluoromethane, about 42 to 46 weightpercent 2,3,3,3-tetrafluoropropene, and about 9 to 13 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 43 to 45 weight percent difluoromethane, about 43 to 45 weightpercent 2,3,3,3-tetrafluoropropene, and about 11 to 13 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 44 weight percent difluoromethane, about 44 weight percent2,3,3,3-tetrafluoropropene, and about 12 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 44 weight percent difluoromethane, about 43 weight percent2,3,3,3-tetrafluoropropene, and about 13 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 55 to 59 weight percent difluoromethane, about 33 to 35 weightpercent 2,3,3,3-tetrafluoropropene, and about 7 to 12 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 57 to 59 weight percent difluoromethane, about 33 to 34 weightpercent 2,3,3,3-tetrafluoropropene, and about 7 to 9 weight percentcarbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 58 weight percent difluoromethane, about 34 weight percent2,3,3,3-tetrafluoropropene, and about 8 weight percent carbon dioxide.

In another embodiment, said refrigerant mixture consisting essentiallyof about 58 weight percent difluoromethane, about 33 weight percent2,3,3,3-tetrafluoropropene, and about 9 weight percent carbon dioxide.

In any of the above embodiment, the total of the refrigerant mixture,must add to 100%.

In one embodiment, the refrigerant mixtures provide replacements forR-32 with cooling capacity within 10% of the cooling capacity for R-32.In another embodiment, the refrigerant mixtures provide replacements forR-32 with cooling capacity within 5% of the cooling capacity for R-32.In another embodiment, the refrigerant mixtures provide replacements forR-32 with cooling capacity within 2% of the cooling capacity for R-32.In another embodiment, the refrigerant mixtures provide replacements forR-32 with cooling capacity that matches or improves upon the coolingcapacity for R-32.

Of particular interest, as replacements for R-32, are compositions aslisted in Table A.

TABLE A R32/R1234yf/CO₂ (wt %) 59/38/3 44/49/7 59/37/4 44/48/8 59/36/544/47/9 59/35/6 44/46/10 59/34/7 44/45/11 59/33/8 44/44/12 59/32/944/43/13 59/31/10 44/42/14 59/30/11 44/41/15 59/29/12 44/40/16 59/28/1344/39/17 58/38/4 43/48/9 58/37/5 43/47/10 58/36/6 43/46/11 58/35/743/45/12 58/34/8 43/44/13 58/33/9 43/43/14 58/32/10 43/42/15 58/31/1143/41/16 47/47/6 43/40/17 47/46/7 42/49/9 47/45/8 42/48/10 47/44/942/47/11 47/43/10 42/46/12 47/42/11 42/45/13 47/41/12 42/44/14 47/40/1342/43/15 47/39/14 42/42/16 47/38/15 42/41/17 47/39/16 48/45/7 49/44/752/41/7 50/43/7 53/40/7 51/42/7 54/38/8 55/37/8 57/35/8 56/36/8 57/36/7

In some embodiments, in addition to the difluoromethane,2,3,3,3-tetrafluoropropene, and carbon dioxide, the disclosedcompositions may comprise optional non-refrigerant components. Thus,disclosed herein are compositions comprising a refrigerant mixtureconsisting essentially of difluoromethane, 2,3,3,3-tetrafluoropropene,and carbon dioxide, further comprising one or more optionalnon-refrigerant components selected from the group consisting oflubricants, dyes (including UV dyes), solubilizing agents,compatibilizers, stabilizers, tracers, anti-wear agents, extremepressure agents, corrosion and oxidation inhibitors, metal surfaceenergy reducers, metal surface deactivators, free radical scavengers,foam control agents, viscosity index improvers, pour point depressants,detergents, viscosity adjusters, and mixtures thereof. In someembodiments, the optional non-refrigerant components may be referred toas additives. Indeed, many of these optional non-refrigerant componentsfit into one or more of these categories and may have qualities thatlend themselves to achieve one or more performance characteristic.

In some embodiments, one or more non-refrigerant components are presentin small amounts relative to the overall composition. In someembodiments, the amount of additive(s) concentration in the disclosedcompositions is from less than about 0.1 weight percent to as much asabout 5 weight percent of the total composition. In some embodiments ofthe present invention, the additives are present in the disclosedcompositions in an amount between about 0.1 weight percent to about 5weight percent of the total composition or in an amount between about0.1 weight percent to about 3.5 weight percent. The additivecomponent(s) selected for the disclosed composition is selected on thebasis of the utility and/or individual equipment components or thesystem requirements.

In one embodiment, the lubricant is selected from the group consistingof mineral oil, alkylbenzene, polyol esters, polyalkylene glycols,polyvinyl ethers, polycarbonates, perfluoropolyethers, silicones,silicate esters, phosphate esters, paraffins, naphthenes,polyalpha-olefins, and combinations thereof.

The lubricants as disclosed herein may be commercially availablelubricants. For instance, the lubricant may be paraffinic mineral oil,sold by BVA Oils as BVM 100 N, naphthenic mineral oils sold by CromptonCo. under the trademarks Suniso® 1GS, Suniso® 3GS and Suniso® 5GS,naphthenic mineral oil sold by Pennzoil under the trademark Sontex®372LT, naphthenic mineral oil sold by Calumet Lubricants under thetrademark Calumet® RO-30, linear alkylbenzenes sold by Shrieve Chemicalsunder the trademarks Zerol® 75, Zerol® 150 and Zerol® 500 and branchedalkylbenzene sold by Nippon Oil as HAB 22, polyol esters (POEs) soldunder the trademark Castor 100 by Castrol, United Kingdom, polyalkyleneglycols (PAGs) such as RL-488A from Dow (Dow Chemical, Midland, Mich.),and mixtures thereof, meaning mixtures of any of the lubricantsdisclosed in this paragraph.

In the compositions of the present invention including a lubricant, thelubricant is present in an amount of less than 40.0 weight percent tothe total composition. In other embodiments, the amount of lubricant isless than 20 weight percent of the total composition. In otherembodiments, the amount of lubricant is less than 10 weight percent ofthe total composition. In other embodiments, the about of lubricant isbetween about 0.1 and 5.0 weight percent of the total composition.

Notwithstanding the above weight ratios for compositions disclosedherein, it is understood that in some heat transfer systems, while thecomposition is being used, it may acquire additional lubricant from oneor more equipment components of such heat transfer system. For example,in some refrigeration, air conditioning and heat pump systems,lubricants may be charged in the compressor and/or the compressorlubricant sump. Such lubricant would be in addition to any lubricantadditive present in the refrigerant in such a system. In use, therefrigerant composition when in the compressor may pick up an amount ofthe equipment lubricant to change the refrigerant-lubricant compositionfrom the starting ratio.

The non-refrigerant component used with the compositions of the presentinvention may include at least one dye. The dye may be at least oneultra-violet (UV) dye. The UV dye may be a fluorescent dye. Thefluorescent dye may be selected from the group consisting ofnaphthalimides, perylenes, coumarins, anthracenes, phenanthracenes,xanthenes, thioxanthenes, naphthoxanthenes, fluoresceins, andderivatives of said dye, and combinations thereof, meaning mixtures ofany of the foregoing dyes or their derivatives disclosed in thisparagraph.

In some embodiments, the disclosed compositions contain from about 0.001weight percent to about 1.0 weight percent UV dye. In other embodiments,the UV dye is present in an amount of from about 0.005 weight percent toabout 0.5 weight percent; and in other embodiments, the UV dye ispresent in an amount of from 0.01 weight percent to about 0.25 weightpercent of the total composition.

UV dye is a useful component for detecting leaks of the composition bypermitting one to observe the fluorescence of the dye at or in thevicinity of a leak point in an apparatus (e.g., refrigeration unit,air-conditioner or heat pump). The UV emission, e.g., fluorescence fromthe dye may be observed under an ultra-violet light. Therefore, if acomposition containing such a UV dye is leaking from a given point in anapparatus, the fluorescence can be detected at the leak point, or in thevicinity of the leak point.

Another non-refrigerant component which may be used with thecompositions of the present invention may include at least onesolubilizing agent selected to improve the solubility of one or more dyein the disclosed compositions. In some embodiments, the weight ratio ofdye to solubilizing agent ranges from about 99:1 to about 1:1. Thesolubilizing agents include at least one compound selected from thegroup consisting of hydrocarbons, hydrocarbon ethers, polyoxyalkyleneglycol ethers (such as dipropylene glycol dimethyl ether), amides,nitriles, ketones, chlorocarbons (such as methylene chloride,trichloroethylene, chloroform, or mixtures thereof), esters, lactones,aromatic ethers, fluoroethers and 1,1,1-trifluoroalkanes and mixturesthereof, meaning mixtures of any of the solubilizing agents disclosed inthis paragraph.

In some embodiments, the non-refrigerant component comprises at leastone compatibilizer to improve the compatibility of one or morelubricants with the disclosed compositions. The compatibilizer may beselected from the group consisting of hydrocarbons, hydrocarbon ethers,polyoxyalkylene glycol ethers (such as dipropylene glycol dimethylether), amides, nitriles, ketones, chlorocarbons (such as methylenechloride, trichloroethylene, chloroform, or mixtures thereof), esters,lactones, aromatic ethers, fluoroethers, 1,1,1-trifluoroalkanes, andmixtures thereof, meaning mixtures of any of the compatibilizersdisclosed in this paragraph.

The solubilizing agent and/or compatibilizer may be selected from thegroup consisting of hydrocarbon ethers consisting of the etherscontaining only carbon, hydrogen and oxygen, such as dimethyl ether(DME) and mixtures thereof, meaning mixtures of any of the hydrocarbonethers disclosed in this paragraph.

The compatibilizer may be linear or cyclic aliphatic or aromatichydrocarbon compatibilizer containing from 3 to 15 carbon atoms. Thecompatibilizer may be at least one hydrocarbon, which may be selectedfrom the group consisting of at least propanes, including propylene andpropane, butanes, including n-butane and isobutene, pentanes, includingn-pentane, isopentane, neopentane and cyclopentane, hexanes, octanes,nonane, and decanes, among others. Commercially available hydrocarboncompatibilizers include but are not limited to those from Exxon Chemical(USA) sold under the trademarks Isopar® H, a mixture of undecane (C₁₁)and dodecane (C₁₂) (a high purity C₁₁ to C₁₂ iso-paraffinic), Aromatic150 (a C₉ to C₁₁ aromatic), Aromatic 200 (a C₉ to C₁₅ aromatic) andNaptha 140 (a mixture of C₅ to C₁₁ paraffins, naphthenes and aromatichydrocarbons) and mixtures thereof, meaning mixtures of any of thehydrocarbons disclosed in this paragraph.

The compatibilizer may alternatively be at least one polymericcompatibilizer. The polymeric compatibilizer may be a random copolymerof fluorinated and non-fluorinated acrylates, wherein the polymercomprises repeating units of at least one monomer represented by theformulae CH₂═C(R¹)CO₂R², CH₂═C(R³)C₆H₄R⁴, and CH₂═C(R⁵)C₆H₄XR⁶, whereinX is oxygen or sulfur; R′, R³, and R⁵ are independently selected fromthe group consisting of H and C₁-C₄ alkyl radicals; and R², R⁴, and R⁶are independently selected from the group consisting ofcarbon-chain-based radicals containing C, and F, and may further containH, Cl, ether oxygen, or sulfur in the form of thioether, sulfoxide, orsulfone groups and mixtures thereof. Examples of such polymericcompatibilizers include those commercially available from E. I. du Pontde Nemours and Company, (Wilmington, Del., 19898, USA) under thetrademark Zonyl® ® PHS. Zonyl® PHS is a random copolymer made bypolymerizing 40 weight percent CH₂═C(CH₃)CO₂CH₂CH₂(CF₂CF₂)_(m)F (alsoreferred to as Zonyl® ® fluoromethacrylate or ZFM) wherein m is from 1to 12, primarily 2 to 8, and 60 weight percent lauryl methacrylate(CH₂═C(CH₃)CO₂(CH₂)₁₁CH₃, also referred to as LMA).

In some embodiments, the compatibilizer component contains from about0.01 to 30 weight percent (based on total amount of compatibilizer) ofan additive which reduces the surface energy of metallic copper,aluminum, steel, or other metals and metal alloys thereof found in heatexchangers in a way that reduces the adhesion of lubricants to themetal. Examples of metal surface energy reducing additives include thosecommercially available from DuPont under the trademarks Zonyr FSA, ZonyrFSP, and Zonyl® FSJ.

Another optional non-refrigerant component which may be used with thecompositions of the present invention may be a metal surfacedeactivator. The metal surface deactivator is selected from the groupconsisting of areoxalyl bis (benzylidene) hydrazide (CAS reg no.6629-10-3), N,N′-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoylhydrazine(CAS reg no. 32687-78-8),2,2,′-oxamidobis-ethyl-(3,5-di-tert-butyl-4-hydroxyhydrocinnamate (CASreg no. 70331-94-1), N,N′-(disalicyclidene)-1,2-diaminopropane (CAS regno. 94-91-7) and ethylenediaminetetra-acetic acid (CAS reg no. 60-00-4)and its salts, and mixtures thereof, meaning mixtures of any of themetal surface deactivators disclosed in this paragraph.

The optional non-refrigerant component used with the compositions of thepresent invention may alternatively be a stabilizer selected from thegroup consisting of hindered phenols, thiophosphates, butylatedtriphenylphosphorothionates, organo phosphates, or phosphites, arylalkyl ethers, terpenes, terpenoids, epoxides, fluorinated epoxides,oxetanes, ascorbic acid, thiols, lactones, thioethers, amines,nitromethane, alkylsilanes, benzophenone derivatives, aryl sulfides,divinyl terephthalic acid, diphenyl terephthalic acid, ionic liquids,and mixtures thereof, meaning mixtures of any of the stabilizersdisclosed in this paragraph.

The stabilizer may be selected from the group consisting of tocopherol;hydroquinone; t-butyl hydroquinone; monothiophosphates; anddithiophosphates, commercially available from Ciba Specialty Chemicals,Basel, Switzerland, hereinafter “Ciba”, under the trademark Irgalube 63;dialkylthiophosphate esters, commercially available from Ciba under thetrademarks Irgalube 353 and Irgalube 350, respectively; butylatedtriphenylphosphorothionates, commercially available from Ciba under thetrademark Irgalube 232; amine phosphates, commercially available fromCiba under the trademark Irgalube 349 (Ciba); hindered phosphites,commercially available from Ciba as Irgafoe 168 andTris-(di-tert-butylphenyl)phosphite, commercially available from Cibaunder the trademark Irgafoe OPH; (Di-n-octyl phosphite); and iso-decyldiphenyl phosphite, commercially available from Ciba under the trademarkIrgafoe DDPP; trialkyl phosphates, such as trimethyl phosphate,triethylphosphate, tributyl phosphate, trioctyl phosphate, andtri(2-ethylhexyl)phosphate; triaryl phosphates including triphenylphosphate, tricresyl phosphate, and trixylenyl phosphate; and mixedalkyl-aryl phosphates including isopropylphenyl phosphate (IPPP), andbis(t-butylphenyl)phenyl phosphate (TBPP); butylated triphenylphosphates, such as those commercially available under the trademarkSyn-O-Ad® including Syn-O-Ad® 8784; tert-butylated triphenyl phosphatessuch as those commercially available under the trademark Durad®20;isopropylated triphenyl phosphates such as those commercially availableunder the trademarks Dura& 220 and Durad®110; anisole;1,4-dimethoxybenzene; 1,4-diethoxybenzene; 1,3,5-trimethoxybenzene;myrcene, alloocimene, limonene (in particular, d-limonene); retinal;pinene; menthol; geraniol; farnesol; phytol; Vitamin A; terpinene;delta-3-carene; terpinolene; phellandrene; fenchene; dipentene;caratenoids, such as lycopene, beta carotene, and xanthophylls, such aszeaxanthin; retinoids, such as hepaxanthin and isotretinoin; bornane;1,2-propylene oxide; 1,2-butylene oxide; n-butyl glycidyl ether;trifluoromethyloxirane; 1,1-bis(trifluoromethyl)oxirane;3-ethyl-3-hydroxymethyl-oxetane, such as OXT-101 (Toagosei Co., Ltd);3-ethyl-3-((phenoxy)methyl)-oxetane, such as OXT-211 (Toagosei Co.,Ltd); 3-ethyl-3-((2-ethyl-hexyloxy)methyl)-oxetane, such as OXT-212(Toagosei Co., Ltd); ascorbic acid; methanethiol (methyl mercaptan);ethanethiol (ethyl mercaptan); Coenzyme A; dimercaptosuccinic acid(DMSA); grapefruit mercaptan((R)-2-(4-methylcyclohex-3-enyl)propane-2-thiol)); cysteine((R)-2-amino-3-sulfanyl-propanoic acid); lipoamide(1,2-dithiolane-3-pentanamide); 5,7-bis(1,1-dimethylethyl)-3-[2,3 (or3,4)-dimethylphenyl]-2(3H)-benzofuranone, commercially available fromCiba under the trademark Irganox® HP-136; benzyl phenyl sulfide;diphenyl sulfide; diisopropylamine; dioctadecyl 3,3′-thiodipropionate,commercially available from Ciba under the trademark Irganox® PS 802(Ciba); didodecyl 3,3′-thiopropionate, commercially available from Cibaunder the trademark Irganoe PS 800;di-(2,2,6,6-tetramethyl-4-piperidyl)sebacate, commercially availablefrom Ciba under the trademark Tinuvie 770;poly-(N-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidyl succinate,commercially available from Ciba under the trademark Tinuvin® 622LD(Ciba); methyl bis tallow amine; bis tallow amine;phenol-alpha-naphthylamine; bis(dimethylamino)methylsilane (DMAMS);tris(trimethylsilyl)silane (TTMSS); vinyltriethoxysilane;vinyltrimethoxysilane; 2,5-difluorobenzophenone;2′,5′-dihydroxyacetophenone; 2-aminobenzophenone; 2-chlorobenzophenone;benzyl phenyl sulfide; diphenyl sulfide; dibenzyl sulfide; ionicliquids; and mixtures and combinations thereof.

The optional non-refrigerant component used with the compositions of thepresent invention may alternatively be an ionic liquid stabilizer. Theionic liquid stabilizer may be selected from the group consisting oforganic salts that are liquid at room temperature (approximately 25°C.), those salts containing cations selected from the group consistingof pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium,pyrazolium, thiazolium, oxazolium and triazolium and mixtures thereof;and anions selected from the group consisting of [BF₄]−, [PF₆]−,[SbF₆]−, [CF₃SO₃]−, [HCF₂CF₂SO₃]−, [CF₃HFCCF₂SO₃]−, [HCCIFCF₂SO₃]−,[(CF₃SO₂)₂N]−, [(CF₃CF₂SO₂)₂N]−, [(CF₃SO₂)₃C]−, [CF₃CO₂]−, and F− andmixtures thereof. In some embodiments, ionic liquid stabilizers areselected from the group consisting of emim BF₄(1-ethyl-3-methylimidazolium tetrafluoroborate); bmim BF₄(1-butyl-3-methylimidazolium tetraborate); emim PF₆(1-ethyl-3-methylimidazolium hexafluorophosphate); and bmim PF₆(1-butyl-3-methylimidazolium hexafluorophosphate), all of which areavailable from Fluka (Sigma-Aldrich).

In some embodiments, the stabilizer may be a hindered phenol, which isany substituted phenol compound, including phenols comprising one ormore substituted or cyclic, straight chain, or branched aliphaticsubstituent group, such as, alkylated monophenols including2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol;2,4-dimethyl-6-tertbutylphenol; tocopherol; and the like, hydroquinoneand alkylated hydroquinones including t-butyl hydroquinone, otherderivatives of hydroquinone; and the like, hydroxylated thiodiphenylethers, including 4,4′-thio-bis(2-methyl-6-tert-butylphenol);4,4′-thiobis(3-methyl-6-tertbutylphenol);2,2′-thiobis(4methyl-6-tert-butylphenol); and the like,alkylidene-bisphenols including:4,4′-methylenebis(2,6-di-tert-butylphenol);4,4′-bis(2,6-di-tert-butylphenol); derivatives of 2,2′- or4,4-biphenoldiols; 2,2′-methylenebis(4-ethyl-6-tertbutylphenol);2,2′-methylenebis(4-methyl-6-tertbutylphenol); 4,4-butylidenebis(3-methyl-6-tert-butylphenol);4,4-isopropylidenebis(2,6-di-tert-butylphenol);2,2′-methylenebis(4-methyl-6-nonylphenol);2,2′-isobutylidenebis(4,6-dimethylphenol;2,2′-methylenebis(4-methyl-6-cyclohexylphenol, 2,2- or 4,4-biphenyldiolsincluding 2,2′-methylenebis(4-ethyl-6-tert-butylphenol); butylatedhydroxytoluene (BHT, or 2,6-di-tert-butyl-4-methylphenol), bisphenolscomprising heteroatoms including2,6-di-tert-alpha-dimethylamino-p-cresol,4,4-thiobis(6-tert-butyl-m-cresol); and the like; acylaminophenols;2,6-di-tert-butyl-4(N,N′-dimethylaminomethylphenol); sulfides including;bis(3-methyl-4-hydroxy-5-tert-butylbenzyl)sulfide;bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide and mixtures thereof,meaning mixtures of any of the phenols disclosed in this paragraph.

In some embodiments, a stabilizer may be a single stabilizing compoundas described in detail above. In other embodiments, a stabilizer may bea mixture of two or more of the stabilizing compounds, either from thesame class of compounds or from differing classes of compounds, saidclasses being described in detail above.

The optional non-refrigerant component, which is used with compositionsof the present invention, may alternatively be a tracer. The tracer maybe two or more tracer compounds from the same class of compounds or fromdifferent classes of compounds. In some embodiments, the tracer ispresent in the compositions at a total concentration of about 1 part permillion by weight (ppm) to about 5000 ppm, based on the weight of thetotal composition. In other embodiments, the tracer is present at atotal concentration of about 10 ppm to about 1000 ppm. In otherembodiments, the tracer is present at a total concentration of about 20ppm to about 500 ppm. In other embodiments, the tracer is present at atotal concentration of about 25 ppm to about 500 ppm. In otherembodiments, the tracer is present at a total concentration of about 50ppm to about 500 ppm. Alternatively, the tracer is present at a totalconcentration of about 100 ppm to about 300 ppm.

The tracer may be selected from the group consisting ofhydrofluorocarbons (HFCs), deuterated hydrofluorocarbons,chlorofluororcarbons (CFCs), hydrofluorochlorocarbons (HCFCs),chlorocarbons, perfluorocarbons, fluoroethers, brominated compounds,iodated compounds, alcohols, aldehydes and ketones, nitrous oxide andcombinations thereof. Alternatively, the tracer may be selected from thegroup consisting of trifluoromethane (HFC-23), dichlorodifluoromethane(CFC-12), chlorodifluoromethane HCFC-22), methyl chloride (R-40),chlorofluoromethane (HCFC-31), fluoroethane (HFC-161),1,1,-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a),chloropentafluoroethane (CFC-115),1,2-dichloro-1,1,2,2-tetrafluoroethane (CFC-114),1,1-dichloro-1,2,2,2-tetrafluoroethane (CFC-114a),2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), pentafluoroethane(HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134),1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1,3,3,3-hexafluoropropane(HFC-236fa), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea),1,1,1,2,2,3,3-heptafluoropropane (HFC-227ea),1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,2-pentafluoropropane(HFC-245cb), 1,1,1,2,3-pentafluoropropane (HFC-245eb),1,1,2,2-tetrafluoropropane (HFC-254cb), 1,1,1,2-tetrafluoropropane(HFC-254eb), 1,1,1-trifluoropropane (HFC-263fb),1,1-difluoro-2-chloroethylene (HCFC-1122),2-chloro-1,1,2-trifluoroethylene (CFC-1113), 1,1,1,3,3-pentafluorobutane(HFC-365mfc), 1,1,1,2,3,4,4,5,5,5-decafluoropentane (HFC-43-10mee),1,1,1,2,2,3,4,5,5,6,6,7,7,7-tetradecafluoroheptane, hexafluorobutadiene,3,3,3-trifluoropropyne, iodotrifluoromethane, deuterated hydrocarbons,deuterated hydrofluorocarbons, perfluorocarbons, fluoroethers,brominated compounds, iodated compounds, alcohols, aldehydes, ketones,nitrous oxide (N₂O) and mixtures thereof. In some embodiments, thetracer is a blend containing two or more hydrofluorocarbons, or onehydrofluorocarbon in combination with one or more perfluorocarbons. Inother embodiments, the tracer is a blend of at least one CFC and atleast one HCFC.

The tracer may be added to the compositions of the present invention inpredetermined quantities to allow detection of any dilution,contamination or other alteration of the composition. Additionally, thetracers may allow detection of product that infringes existing patentrights, by identification of the patent owner's product versuscompetitive infringing product. Further, in one embodiment, the tracercompounds may allow detection of a manufacturing process by which aproduct is produced, thus, allowing detection of infringement of apatent to specific manufacturing process chemistry.

The additive which may be used with the compositions of the presentinvention may alternatively be a perfluoropolyether as described indetail in US2007-0284555, incorporated herein by reference.

It will be recognized that certain of the additives referenced above assuitable for the non-refrigerant component have been identified aspotential refrigerants. However, in accordance with this invention, whenthese additives are used, they are not present at an amount that wouldaffect the novel and basic characteristics of the refrigerant mixturesof this invention. Preferably, the refrigerant mixtures and thecompositions of this invention containing them, contain no more thanabout 0.5 weight percent of the refrigerants other than HFC-32,HFO-1234yf, and CO₂.

In one embodiment, the compositions disclosed herein may be prepared byany convenient method to combine the desired amounts of the individualcomponents. A preferred method is to weigh the desired component amountsand thereafter combine the components in an appropriate vessel.Agitation may be used, if desired.

Compositions of the present invention have zero ozone depletionpotential and low global warming potential (GWP). Additionally, thecompositions of the present invention will have global warmingpotentials that are less than many hydrofluorocarbon refrigerantscurrently in use.

Apparatus and Methods of Use

The compositions disclosed herein are useful as heat transfercompositions or refrigerants. In particular, the compositions comprisingHFC-32, HFO-1234yf, and CO₂ are useful as refrigerants. Also, thecompositions comprising HFC-32, HFO-1234yf, and CO₂ are useful asreplacements for or R-410A in refrigeration, air conditioning or heatpump systems. In particular, the compositions comprising a refrigerantmixture consisting essentially of HFC-32, HFO-1234yf, and CO₂ are usefulas replacements for R-32 in air conditioning and heat pump systems andapparatus. Alternatively, the compositions comprising a refrigerantmixture consisting of HFC-32, HFO-1234yf, and CO₂ are useful asreplacements for R-32 in air conditioning and heat pump systems andapparatus.

Thus, disclosed herein is a process for producing cooling comprisingevaporating a composition comprising a refrigerant mixture consistingessentially of HFC-32, HFO-1234yf, and CO₂, in the vicinity of a body tobe cooled, and thereafter condensing said composition. Alternatively,the process for producing cooling comprises evaporating a compositioncomprising a refrigerant mixture consisting of HFC-32, HFO-1234yf, andCO₂ in the vicinity of a body to be cooled and thereafter condensingsaid composition.

In another embodiment, disclosed herein is a process for producingheating comprising evaporating a composition comprising a refrigerantmixture consisting essentially of HFC-32, HFO-1234yf, and CO₂ andthereafter condensing said composition in the vicinity of a body to beheated. Alternatively, the process for producing heating comprisesevaporating a composition comprising a refrigerant mixture consisting ofHFC-32, HFO-1234yf, and CO₂ and thereafter condensing said compositionin the vicinity of a body to be heated

Vapor-compression refrigeration, air conditioning and heat pump systemsinclude an evaporator, a compressor, a condenser, and an expansiondevice. A refrigeration cycle re-uses refrigerant in multiple stepsproducing a cooling effect in one step and a heating effect in adifferent step. The cycle can be described simply as follows. Liquidrefrigerant enters an evaporator through an expansion device, and theliquid refrigerant boils in the evaporator, by withdrawing heat from theenvironment, at a low temperature to form a gas and produce cooling.Often air or a heat transfer fluid flows over or around the evaporatorto transfer the cooling effect caused by the evaporation of therefrigerant in the evaporator to a body to be cooled. The low-pressuregas enters a compressor where the gas is compressed to raise itspressure and temperature. The higher-pressure (compressed) gaseousrefrigerant then enters the condenser in which the refrigerant condensesand discharges its heat to the environment. The refrigerant returns tothe expansion device through which the liquid expands from thehigher-pressure level in the condenser to the low-pressure level in theevaporator, thus repeating the cycle.

A body to be cooled or heated may be defined as any space, location,object or body for which it is desirable to provide cooling or heating.Examples include spaces (open or enclosed) requiring air conditioning,cooling, or heating, such as a room, an apartment, or building, such asan apartment building, university dormitory, townhouse, or otherattached house or single family home, hospitals, office buildings,supermarkets, college or university classrooms or administrationbuildings and automobile or truck passenger compartments.

By “in the vicinity of” is meant that the evaporator of the systemcontaining the refrigerant composition is located either within oradjacent to the body to be cooled, such that air moving over theevaporator would move into or around the body to be cooled. In theprocess for producing heating, “in the vicinity of” means that thecondenser of the system containing the refrigerant composition islocated either within or adjacent to the body to be heated, such thatthe air moving over the evaporator would move into or around the body tobe heated.

A method is provided for replacing R-32 in air conditioning or heat pumpsystems comprising replacing said R-32 with a composition comprising arefrigerant, air conditioning or heat pump system in place of R-32.Alternatively, the method for replacing R-32 in air conditioning or heatpump systems comprises replacing said R-32 with a composition comprisinga refrigerant mixture consisting of HFC-32, HFO-1234yf, and CO₂ to saidair conditioning or heat pump system in place of R-32.

Often replacement refrigerants are most useful if capable of being usedin the original refrigeration equipment designed for a differentrefrigerant. Additionally, the compositions as disclosed herein may beuseful as replacements for R-32 in equipment designed for R-32 withminimal to no system modifications. Further, the compositions may beuseful for replacing R-32 in equipment specifically modified for orproduced entirely for these new compositions comprising HFC-32,HFO-1234yf, and CO₂.

In many applications, some embodiments of the disclosed compositions areuseful as refrigerants and provide at least comparable coolingperformance (meaning cooling capacity) as the refrigerant for which areplacement is being sought.

In one embodiment is provided a method for replacing R-32 comprisingcharging an air conditioning or heat pump system with a compositioncomprising HFC-32, HFO-1234yf, and CO₂ as replacement for said R-32.

In one embodiment of the method, the cooling capacity provided by thecomposition comprising a refrigerant mixture consisting essentially ofHFC-32, HFO-1234yf, and CO₂ is within about ±10% of that produced byR-32 under the same operating conditions. In another embodiment of themethod, the cooling capacity provided by the composition comprising arefrigerant mixture consisting essentially of HFC-32, HFO-1234yf, andCO₂ is within about ±5% of that produced by R-32 under the sameoperating conditions. In another embodiment of the method, the coolingcapacity provided by the composition comprising a refrigerant mixtureconsisting essentially of HFC-32, HFO-1234yf, and CO₂ is within about±2% of that produced by R-32 under the same operating conditions.

Additionally, disclosed herein is an air conditioning or heat pumpsystem comprising an evaporator, compressor, condenser and an expansiondevice characterized by containing a composition comprising HFC-32,HFO-1234yf, and CO₂.

It has been found that the compositions of the present invention willhave some temperature glide in the heat exchangers. Thus, the systemswill operate more efficiently if the heat exchangers are operated incounter-current mode or cross-current mode with counter-currenttendency. Counter-current tendency means that the closer the heatexchanger can get to counter-current mode the more efficient the heattransfer. Thus, air conditioning heat exchangers, in particular,evaporators, are designed to provide some aspect of counter-currenttendency. Therefore, provided herein is an air conditioning or heat pumpsystem wherein said system includes one or more heat exchangers (eitherevaporators, condensers or both) that operate in counter-current mode orcross-current mode with counter-current tendency.

Additionally, the compositions of the present invention can be used insystems with heat exchangers operating in cross-current mode.

In another embodiment, provided herein is a refrigeration system whereinsaid system includes one or more heat exchangers (either evaporators,condensers or both) that operate in counter-current mode, cross-currentmode, or cross-current mode with counter-current tendency.

In one embodiment, the refrigeration, air conditioning or heat pumpsystem is a stationary refrigeration, air conditioning or heat pumpsystem. In another embodiment the refrigeration, air conditioning orheat pump system is a mobile refrigeration, air conditioning or heatpump system.

Additionally, in some embodiments, the disclosed compositions mayfunction as primary refrigerants in secondary loop systems that providecooling to remote locations by use of a secondary heat transfer fluid,which may comprise water, an aqueous salt solution (e.g., calciumchloride), a glycol, carbon dioxide, or a fluorinated hydrocarbon fluid.In this case the secondary heat transfer fluid is the body to be cooledas it is adjacent to the evaporator and is cooled before moving to asecond remote body to be cooled.

Examples of air conditioning or heat pump systems include but are notlimited to air conditioners, residential heat pumps, chillers, includingflooded evaporator chillers and direct expansion chillers, mobile airconditioning units, dehumidifiers, and combinations thereof.

As used herein, mobile refrigeration, air conditioning or heat pumpsystems refers to any refrigeration, air conditioner or heat pumpapparatus incorporated into a transportation unit for the road, rail,sea or air. Mobile air conditioning or heat pumps systems may be used inautomobiles, trucks, railcars or other transportation systems. Mobilerefrigeration may include transport refrigeration in trucks, airplanes,or rail cars. In addition, apparatus which are meant to providerefrigeration for a system independent of any moving carrier, known as“intermodal” systems, are including in the present inventions. Suchintermodal systems include “containers” (combined sea/land transport) aswell as “swap bodies” (combined road and rail transport).

As used herein, stationary air conditioning or heat pump systems aresystems that are fixed in place during operation. A stationary airconditioning or heat pump system may be associated within or attached tobuildings of any variety. These stationary applications may bestationary air conditioning and heat pumps, including but not limited tochillers, heat pumps, including residential and high temperature heatpumps, residential, commercial or industrial air conditioning systems,and including window, ductless, ducted, packaged terminal, and thoseexterior but connected to the building such as rooftop systems.

Examples of refrigeration systems the disclosed compositions may beuseful in are equipment including commercial, industrial or residentialrefrigerators and freezers, ice machines, self-contained coolers andfreezers, flooded evaporator chillers, direct expansion chillers,walk-in and reach-in coolers and freezers, and combination systems. Insome embodiments, the disclosed compositions may be used in supermarketrefrigeration systems. Additionally, stationary applications may utilizea secondary loop system that uses a primary refrigerant to producecooling in one location that is transferred to a remote location via asecondary heat transfer fluid.

In the air conditioning and heat pump system of the present invention,the heat exchangers will operate within certain temperature limitations.For air conditioning, in one embodiment, the evaporator will operate atmidpoint temperature of about 0° C. to about 20° C. In anotherembodiment, the evaporator will operate at midpoint temperature of about0° C. to about 15° C. In yet another embodiment, the evaporator willoperate at midpoint temperature of about 5° C. to about 10° C. In oneembodiment, the condenser will operate at midpoint temperature of about15° C. to about 60° C. In another embodiment, the condenser will operateat midpoint temperature of about 20° C. to about 60° C.

EXAMPLES

The concepts disclosed herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

Example Cooling Performance

Cooling performance at typical conditions for air conditioning and heatpump apparatus for compositions of the present invention is determinedand displayed in Table 1 as compared to R-32. The GWP values are fromthe Intergovernmental Panel on Climate Change (IPCC) Fourth AssessmentReport, Working Group I, 2007 (AR4). Average temperature glide (AverageTemp Glide:

the average of the temperature glide in the evaporator and thetemperature glide in the condenser), cooling capacity (Capacity), andcompressor discharge temperatures (Compr Disch Temp) are calculated fromphysical property measurements for the compositions of the presentinvention at the following specific conditions:

Evaporator temperature 50° F. (10° C.) Condenser temperature 115° F.(46.1° C.) Amount of superheat 20° F. (11.1 K) Amount of subcooling 15°F. (8.3 K) Compressor efficiency 70%

TABLE 1 Relative Relative Average Capacity COP to Compr Composition GWPTemp to R-32 R-32 Disch (wt %) (AR4) Glide, ° C. (%) (%) Temp, ° C. R-32(100) 675 0 100 100 84 Comparative compositions R32/R1234yf/CO₂, wt %40/51/9 272 8.3 89.8% 95% 74 21.5/75.5/3 148 8.4 65.3% 98% 6521.5/72.5/6 148 10.5 71.8% 97% 68 21.5/69.5/9 148 12.3 78.3% 97% 71R32/R1234yf 44/56 299 3.5 76.1% 100%  80 R32/R1234yf/CO₂, wt % 59/37/4399.8 3.9 91.8% 99% 87 59/36/5 399.7 4.4 93.8% 98% 88 59/35/6 400 4.895.7% 98% 89 59/34/7 400 5.3 97.7% 98% 90 59/33/8 400 5.7 99.6% 97% 9059/32/9 400 6.1  102% 97% 91 59/31/10 400 6.4  104% 97% 92 59/30/11 4006.7  106% 97% 93 59/29/12 400 7.0  107% 96% 93 59/28/13 400 7.3  109%96% 94 58/38/4 393 4.0 91.3% 99% 87 58/37/5 393 4.5 93.3% 98% 88 58/36/6393 4.9 95.3% 98% 89 58/35/7 393 5.4 97.2% 98% 89 58/34/8 393 5.8 99.2%97% 90 58/33/9 393 6.2  101% 97% 91 58/32/10 393 6.5  103% 97% 9258/31/11 393 6.8  105% 97% 92 57/35/8 386 5.9 96.8% 98% 87.1 56/36/8 3806.0 96.3% 98% 86.8 55/37/8 373 6.1 95.8% 98% 86.4 54/38/8 366 6.2 95.3%98% 86.1 53/40/7 359 5.9 92.9% 98% 85.3 52/41/7 353 6.1 92.4% 98% 84.951/42/7 346 6.2  9.8% 98% 84.6 50/43/7 339 6.3 91.3% 98% 84.3 49/44/7333 6.5 90.7.%  98% 84.0 48/45/7 326 6.6 90.1% 98% 83.7 47/46/7 319 6.791.7% 98% 87 47/45/8 319 7.2 93.7% 97% 87 47/44/9 319 7.6 95.7% 97% 8847/43/10 319 8.0 97.8% 97% 89 47/42/11 319 8.3  100% 97% 90 47/41/12 3198.7  102% 96% 90 47/40/13 319 9.0  104% 96% 91 47/39/14 319 9.2  106%96% 91 47/38/15 319 9.5  108% 95% 92 47/39/16 319 9.7  110% 95% 9344/49/7 299 7.2 90.1% 98% 86 44/48/8 299 7.7 92.1% 98% 87 44/47/9 2998.1 94.2% 97% 87 44/46/10 299 8.5 96.2% 97% 88 44/45/11 299 8.8 98.2%97% 89 44/44/12 299 9.2  100% 96% 89 44/43/13 299 9.5  102% 96% 9044/42/14 299 9.8  104% 96% 91 44/41/15 299 10.0  106% 95% 91 44/40/16299 10.3  108% 95% 92 44/39/17 299 10.5  110% 95% 93 43/48/9 292 8.090.7% 94% 83 43/47/10 292 8.4 92.5% 94% 84 43/46/11 292 8.7 94.3% 93% 8443/45/12 292 9.0 96.1% 93% 85 43/44/13 292 9.3 97.9% 93% 86 43/43/14 2929.6  100% 92% 86 43/42/15 292 9.8  101% 92% 87 43/41/16 292 10.1  103%91% 87 43/40/17 292 10.3  105% 91% 87 42/49/9 286 8.2 90.1% 94% 8342/48/10 286 8.5 91.8% 94% 84 42/47/11 285 8.9 93.6% 93% 84 42/46/12 2859.2 95.4% 93% 85 42/45/13 285 9.5 97.2% 92% 85 42/44/14 285 9.8 99.0%92% 86 42/43/15 285 10.0  101% 92% 86 42/42/16 285 10.2  103% 91% 8742/41/17 285 10.4  104% 91% 87

All the compositions of the present invention provided in Table 1provide volumetric capacity within ±10% of that for R-32, whileproviding average temperature glide less than 8° C. and havingreasonable compressor discharge temperatures as compared to R-32. Manyof the compositions of Table 1 provide volumetric capacity within ±5% ofthat for R-32. Additionally, some of the compositions of Table 1 providevolumetric capacity within ±2% of that for R-32. And all of thecompositions show reasonable energy efficiency (as COP relative toR-32).

Selected Embodiments

Embodiment A1: A composition comprising a refrigerant mixture forreplacing R-32 said refrigerant mixture consisting essentially ofdifluoromethane, 2,3,3,3-tetrafluoropropene, and carbon dioxide.

Embodiment A2: The composition of Embodiment A1, said refrigerantmixture consisting essentially of from about 42 to about 59 weightpercent difluoromethane, about 28 to about 53 weight percent2,3,3,3-tetrafluoropropene, and about 4 to about 17 weight percentcarbon dioxide.

Embodiment A3: The composition of any of Embodiments A1 and A2, saidrefrigerant mixture consisting essentially of from about 42 to about 59weight percent difluoromethane, about 31 to about 49 weight percent2,3,3,3-tetrafluoropropene, and about 4 to about 17 weight percentcarbon dioxide.

Embodiment A4: The composition of any of Embodiments A1-A3, saidrefrigerant mixture consisting essentially of from about 42 to about 59weight percent difluoromethane, about 33 to about 48 weight percent2,3,3,3-tetrafluoropropene, and about 6 to about 15 weight percentcarbon dioxide.

Embodiment A5: The composition of any of Embodiments A1-A4, saidrefrigerant mixture consisting essentially of about 42 to 59 weightpercent difluoromethane, about 33 to 46 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 17 weight percent carbondioxide.

Embodiment A6: The composition of any of Embodiments A1-A5, saidrefrigerant mixture consisting essentially of about 47 to 59 weightpercent difluoromethane, about 32 to 47 weight percent2,3,3,3-tetrafluoropropene, and about 8 to 13 weight percent carbondioxide.

Embodiment A7: The composition of any of Embodiments A1-A6, saidrefrigerant mixture consisting essentially of about 47 to 59 weightpercent difluoromethane, about 28 to 46 weight percent2,3,3,3-tetrafluoropropene, and about 4 to 16 weight percent carbondioxide.

Embodiment A8: The composition of any of Embodiments A1-A7, saidrefrigerant mixture consisting essentially of about 47 to 59 weightpercent difluoromethane, about 31 to 44 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 13 weight percent carbondioxide.

Embodiment A9: The composition of any of Embodiments A1-A8, saidrefrigerant mixture consisting essentially of about 47 to 59 weightpercent difluoromethane, about 32 to 42 weight percent2,3,3,3-tetrafluoropropene, and about 8 to 12 weight percent carbondioxide.

Embodiment A10: The composition of any of Embodiments A1-A7, saidrefrigerant mixture consisting essentially of about 42 to 59 weightpercent difluoromethane, about 32 to 45 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 15 weight percent carbondioxide.

Embodiment A11: The composition of any of Embodiments A1-A2, saidrefrigerant mixture consisting essentially of about 44 to 47 weightpercent difluoromethane, about 45 to 50 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 15 weight percent carbondioxide.

Embodiment A12: The composition of any of Embodiments A1-A2, and A11,said refrigerant mixture consisting essentially of about 42 to 44 weightpercent difluoromethane, about 45 to 50 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 13 weight percent carbondioxide.

Embodiment A13: The composition of any of Embodiments A1-A2, A11 andA12, said refrigerant mixture consisting essentially of about 42 to 44weight percent difluoromethane, about 45 to 50 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 13 weight percent carbondioxide.

Embodiment A14: The composition of any of Embodiments A1-A3 and A11-A13,said refrigerant mixture consisting essentially of about 42 to 44 weightpercent difluoromethane, about 48 to 49 weight percent2,3,3,3-tetrafluoropropene, and about 7 to 10 weight percent carbondioxide.

Embodiment A15: The composition of any of Embodiments A1-A3 and A11-A14,said refrigerant mixture consisting essentially of about 43 to 44 weightpercent difluoromethane, about 48 to 49 weight percent2,3,3,3-tetrafluoropropene, and about 6 to 8 weight percent carbondioxide.

Embodiment A16: The composition of any of Embodiments A1-A3 and A11-A15,said refrigerant mixture consisting essentially of about 44 weightpercent difluoromethane, about 49 weight percent2,3,3,3-tetrafluoropropene, and about 7 weight percent carbon dioxide.

Embodiment A17: The composition of any of Embodiments A1-A7, saidrefrigerant mixture consisting essentially of about 43 to 45 weightpercent difluoromethane, about 42 to 46 weight percent2,3,3,3-tetrafluoropropene, and about 9 to 13 weight percent carbondioxide.

Embodiment A18: The composition of any of Embodiments A1-A7 and A17,said refrigerant mixture consisting essentially of about 43 to 45 weightpercent difluoromethane, about 43 to 45 weight percent2,3,3,3-tetrafluoropropene, and about 11 to 13 weight percent carbondioxide.

Embodiment A19: The composition of any of Embodiments A1-A7 and A17-A18said refrigerant mixture consisting essentially of about 44 weightpercent difluoromethane, about 44 weight percent2,3,3,3-tetrafluoropropene, and about 12 weight percent carbon dioxide.

Embodiment A20: The composition of any of Embodiments A1-A7 and A17-A18said refrigerant mixture consisting essentially of about 44 weightpercent difluoromethane, about 43 weight percent2,3,3,3-tetrafluoropropene, and about 13 weight percent carbon dioxide.

Embodiment A21: The composition of any of Embodiments A1-A10, saidrefrigerant mixture consisting essentially of about 55 to 59 weightpercent difluoromethane, about 33 to 35 weight percent2,3,3,3-tetrafluoropropene, and about 7 to 12 weight percent carbondioxide.

Embodiment A22: The composition of any of Embodiments A1-A10 and A21,said refrigerant mixture consisting essentially of about 57 to 59 weightpercent difluoromethane, about 33 to 34 weight percent2,3,3,3-tetrafluoropropene, and about 7 to 9 weight percent carbondioxide.

Embodiment A23: The composition of any of Embodiments A1-A10 andA21-A22, said refrigerant mixture consisting essentially of about 58weight percent difluoromethane, about 34 weight percent2,3,3,3-tetrafluoropropene, and about 8 weight percent carbon dioxide.

Embodiment A24: The composition of any of Embodiments A1-A10 andA21-A23, said refrigerant mixture consisting essentially of about 58weight percent difluoromethane, about 33 weight percent2,3,3,3-tetrafluoropropene, and about 9 weight percent carbon dioxide.

Embodiment A25: The composition of any of Embodiments A1-A24, furthercomprising one or more components selected from the group consisting oflubricants, dyes, solubilizing agents, compatibilizers, stabilizers,tracers, anti-wear agents, extreme pressure agents, corrosion andoxidation inhibitors, metal surface energy reducers, metal surfacedeactivators, free radical scavengers, foam control agents, viscosityindex improvers, pour point depressants, detergents, viscosityadjusters, and mixtures thereof.

Embodiment A26: The composition of any of Embodiments A1-A25, whereinsaid lubricant is selected from the group consisting of mineral oil,alkylbenzene, polyol esters, polyalkylene glycols, polyvinyl ethers,polycarbonates, perfluoropolyethers, synthetic paraffins, syntheticnaphthenes, polyalpha-olefins, and combinations thereof.

Embodiment A27: The composition of any of Embodiments A1-A24, furthercomprising a lubricant selected from the group consisting of mineraloil, alkylbenzene, polyol esters, polyalkylene glycols, polyvinylethers, polycarbonates, perfluoropolyethers, synthetic paraffins,synthetic naphthenes, polyalpha-olefins, and combinations thereof.

Embodiment B1: A process for producing cooling comprising condensing thecomposition of any of Embodiments A1-A25 and thereafter evaporating saidcomposition in the vicinity of a body to be cooled.

Embodiment B2: A process for producing heating comprising evaporatingcomposition of any of Embodiments A1-A25 and thereafter condensing saidcomposition in the vicinity of a body to be heated.

Embodiment B3: The process of any of Embodiment B1 or B2, wherein saidevaporating is completed in an evaporation and wherein said evaporatoroperates with midpoint temperatures between about 0° C. to about 20° C.

Embodiment C1: A method of replacing R-32 in air conditioning or heatpump systems comprising providing the composition of any of EmbodimentsA1-A25 to the system as replacement for said R-32 in said airconditioning or heat pump system.

Embodiment C2: The method of Embodiments C1, wherein said airconditioning or heat pump system comprises at least one evaporator andsaid evaporator operates with midpoint temperatures between about 0° C.to about 20° C.

Embodiment D1: An air conditioning or heat pump system comprising anevaporator, compressor, condenser and expansion device characterized bycontaining the composition of any of Embodiments A1-A25.

Embodiment D2: The air conditioning or heat pump system of EmbodimentD1, wherein said system includes one or more heat exchangers thatoperate in counter-current mode, cross-current mode, or cross-currentmode with counter-current tendency.

Embodiment D3: The air conditioning or heat pump system of Embodiment D1or D2, wherein the evaporator operates with midpoint temperaturesbetween about 0° C. to about 20° C.

Embodiment E1: The compositions of any of Embodiments A1-A25, theprocesses of any of Embodiments B1-63, the methods of Embodiments C1 orC2, or the systems of any of Embodiments D1-D3, wherein the refrigerantmixture has a GWP of 400 or less.

Embodiment E2: The compositions of any of Embodiments A1-A25, theprocesses of any of Embodiments B1-63, the methods of Embodiments C1 orC2, or the systems of any of Embodiments D1-D3, wherein the refrigerantmixture has a GWP of 300 or less.

What is claimed is: 1-23. (canceled)
 24. A composition for replacingR-32 consisting essentially of from about 42 to about 44 weight percentdifluoromethane, about 45 to about 50 weight percent2,3,3,3-tetrafluoropropene, and about 6 to about 13 weight percentcarbon dioxide, wherein the composition provides volumetric capacitywithin 5% of that for R-32, average temperature glide of less than 10°C., and a GWP of less than
 300. 25. The composition of claim 24consisting of about 42 to 44 weight percent difluoromethane, about 42 to49 weight percent 2,3,3,3-tetrafluoropropene, and about 7 to 13 weightpercent carbon dioxide.
 26. The composition of claim 24, saidrefrigerant mixture consisting of about 42 to 44 weight percentdifluoromethane, about 48 to 49 weight percent2,3,3,3-tetrafluoropropene, and about 7 to 10 weight percent carbondioxide.
 27. The composition of claim 24, said refrigerant mixtureconsisting of about 43 to 44 weight percent difluoromethane, about 48 to49 weight percent 2,3,3,3-tetrafluoropropene, and about 6 to 8 weightpercent carbon dioxide.
 28. The composition of claim 24, saidrefrigerant mixture consisting essentially of about 44 weight percentdifluoromethane, about 49 weight percent 2,3,3,3-tetrafluoropropene, andabout 7 weight percent carbon dioxide.
 29. A process for producingcooling comprising condensing the composition of claim 24 and thereafterevaporating said composition in the vicinity of a body to be cooled. 30.A process for producing heating comprising evaporating the compositionof claim 24 and thereafter condensing said composition in the vicinityof a body to be heated.
 31. A method of replacing R-32 in refrigeration,air conditioning or heat pump systems comprising providing thecomposition of claim 24 as replacement for said R-32.
 32. An airconditioning or heat pump system comprising an evaporator, compressor,condenser and expansion device characterized by containing thecomposition of claim
 24. 33. The air conditioning or heat pump system ofclaim 32, wherein said system includes one or more heat exchangers thatoperate in counter-current mode, cross-current mode, or cross-currentmode with counter-current tendency.
 34. A composition for replacing R-32consisting of: (a) from about 42 to about 44 weight percentdifluoromethane, about 45 to about 50 weight percent2,3,3,3-tetrafluoropropene, and about 6 to about 13 weight percentcarbon dioxide, and (b) one or more components selected from the groupconsisting of lubricants, dyes, solubilizing agents, compatibilizers,stabilizers, tracers, anti-wear agents, extreme pressure agents,corrosion and oxidation inhibitors, metal surface energy reducers, metalsurface deactivators, free radical scavengers, foam control agents,viscosity index improvers, pour point depressants, detergents, viscosityadjusters, and mixtures thereof wherein the composition providesvolumetric capacity within 5% of that for R-32, average temperatureglide of less than 10° C., and a GWP of less than
 300. 35. Thecomposition of claim 34, wherein said lubricant is selected from thegroup consisting of mineral oil, alkylbenzene, polyol esters,polyalkylene glycols, polyvinyl ethers, polycarbonates,perfluoropolyethers, synthetic paraffins, synthetic naphthenes,polyalpha-olefins, and combinations thereof.
 36. A method of replacingR-32 in air conditioning or heat pump systems comprising providing thecomposition of claim 34 as replacement for said R-32 in said airconditioning or heat pump system.
 37. An air conditioning or heat pumpsystem comprising an evaporator, a compressor, a condenser, and anexpansion device, characterized by containing the composition of claim34.